1. Field of the Invention
The present invention relates generally to video technology and, more particularly, to the enhancement of a video image.
2. Description of the Related Art
For most people in the United States, television is a normal part of their everyday lives. Television entertains, relaxes, and informs. In fact, using satellite communication, televisions have been generally credited with bringing the world closer together in the last twenty to thirty years.
It is, therefore, somewhat ironic that television technology arose out of the development of RADAR during World War II, from which evolved the high frequency circuits necessary for the introduction of television in 1945. Television became instantly popular, and technological advances over the past fifty years have enhanced its popularity. The improvements seem to be never ending. Just a few of the more significant improvements include: color picture, electronic tuners, coaxial cable signal transmission, the replacement of vacuum tube circuits with solid state circuits, and, of course, infrared remote controls.
Although the technologic advancement of the past fifty years has greatly improved television in almost every way imaginable, from picture quality to reliability, the television that we watch today still uses the standard developed by the National Television Systems Committee (NTSC) in the late 1940s. The incorporation of color in the NTSC standard approximately forty years ago marked its last major advancement. The NTSC's standardization activities were subsequently emulated throughout the world, leading to the development of other standards such as PAL and SECAM. Although new standards have been proposed from time to time in an effort to promote further forward leaps in technology for the improvement of television, the United States government and most foreign governments have been somewhat reluctant to stray from these long standing standards. The primary reason for this reluctance appears to be the governments' desire to protect the investments consumers have made in their television equipment. In other words, any new standard must be compatible with television equipment that consumers may have purchased many years before.
By way of example, let us consider the circumstances surrounding the evolution of television from its monochromatic (black and white) roots to the color video images that we are all familiar with today. For more than a decade after its introduction, television images were monochromatic. In other words, the video signal conveyed information relating primarily to brightness variations, much as does a black and white photograph. This monochromatic video signal is typically referred to as a luminance signal. However, to describe a color, the video signal needed to contain additional information. The government determined that any color system must produce a signal that is recognizable to a monochrome receiver as well as a color receiver, so that the viewer has a choice between a black and white television set or a color television set. Therefore, to incorporate the color information in the transmission signal, the NTSC determined that the luminance signal would remain unchanged and that the color signal would be added to the luminance signal. This color signal is typically referred to as the chrominance (or chroma) signal.
In color television sets, the analog luminance and chrominance signals are converted to a red-green-blue (RGB) format and used to drive the RGB electron guns that, in turn, excite the phosphors on the picture tube to produce the desired color video images. As most viewers know, various characteristics of a color video image may be adjusted to suit a viewer's taste. Such characteristics include brightness, contrast, color strength, tint, and sharpness. While each of these characteristics is important for the viewer's enjoyment of the television, the sharpness characteristic has become particularly important in this new era of digital television, multimedia, and PC TV. This newfound importance results from the increased use of graphics in the video images displayed by television monitors. These graphics may be superimposed on a typical broadcast video image, or the graphics may be displayed by the television monitor when used as a computer monitor.
The present invention is directed to overcoming, or at least reducing the affects of, one or more problems set forth above.